No. 1 Marius De Romanus Hater

The first is Louis.

Louis is Lestat's companion and endgame. In a show adaptation of TTOTBT, there is no reason why they would not have Louis be the one to go on a rescue caper with Lestat. Daniel certainly isn't going to. They're not friends. I don't know that they're ever going to come back from Daniel hacking his head off.

The second is Raglan James.

Raglan James in the book is ex-Talamasca because he's been sacked for being a fucking freak. In the show he is still a fucking freak but he—like David Talbot—is a current Talamasca agent. Raglan is also apparently, by the time of the recording of The Failures, someone who Lestat considers a friend. Much in the same way that, by the end of QOTD, Lestat randomly, seemingly out of nowhere is besties with David Talbot leading into TTOTBT.

Now, some people are concerned that, because the last time we see Daniel he's squaring up with Raglan, he's about to get implicated in the whole body swap fiasco, but TO ME, that scene is all about Raglan having his lightbulb moment.

Personally I think that moment for Raglan, the confirmation of a soul, was the first time he's really considered that he could actually steal a body. The fact that he looks over to Lestat's head in the bag and then goes on to ingratiate himself in Lestat's circle, indicates that Lestat's is the one he wants (obviously, that's the body he steals after all).

All of this is to say that in the show universe, there is no reason for TTOTBT plot to involve a random third person who ends up permanently inhabiting an extra body. Is it a convenient option to have open on the off-chance they did need to replace Eric for some reason? Sure, I guess. But from all the vibes I'm getting, Eric is giving no indication of wanting to leave this show. Even in the Backstage Pass Short after the finale he's like, "I fantasize about the power of vampires, I can't wait to fight everyone". The man is locked in.

So no, Daniel is not "taking on David Talbot's storyline" in the show. He's being set up to fulfil Daniel's OWN storyline, that being the Devil's Minion arc. He merely has been given some traits that once belonged to David Talbot. As has Louis. As has Raglan James. A direct swap between Raglan and Lestat is all that needs to happen in an adaptation of TTOTBT. An extra body is superfluous.